GRD Journals Global Research and Development Journal for Engineering International Conference on Innovations in Engineering and Technology (ICIET) - 2016 July 2016 e-issn: 2455-5703 Design of Metamaterial Antenna For Wireless Applications 1 G. Pradeepa 2 M. Ameena Banu 3 A. C. Shagar 1 P.G Scholar 2 Associate Professor 3 Professor 1,2,3 Department of Electronics and Communication Engineering 1,2,3 Sethu Institute of Technology, Pulloor, Kariapatti, Virudhunagar 626115 India Abstract A multiband compact planar antenna was designed with frequency notched function, the antenna with CPW fed is consist of various microstrip resonators, such as closed ring resonator and SRR, producing some discontinuous resonant bands is suggested. Metamaterial is artificial material that may exhibit electromagnetic (EM) responses not readily found in natural. Presently, it has gained considerable attention since its unique EM characteristics can be advantageous in design of novel EM components and devices. It may be used for making perfect lens or even invisibility cloaks. Other examples are that electromagnetic band gap/photonic band gap (EBG/PBG) and artificial magnetic metamaterial have already been used in antennas design, which might be used to open the door to obtain the compact and high performance EM components and devices. Using Agilent Technologies ADS Software, the antenna is designed and simulated for 2.1/3.5/5GHZ UMTS/worldwide interoperability for microwave access (WiMAX)/Wireless LAN (WLAN) application with return loss of more than -10dB. To achieve a very wide bandwidth the rectangular ground planes and the split-ring loops dimensions are tuned. to improve the return loss performance in the required band a tapered transmission line is adopted. Measurement results shows that the proposed UWB antennas have a wide bandwidth from 3.1 to 10.6 GHz. To achieve a very wide bandwidth the rectangular ground planes and the split-ring loops dimensions are tuned. Keyword- SRR, spilt ring loops, closed ring resonator I. INTRODUCTION In recent years metamaterials are mostly used for antenna applications. Metamaterials are used in antenna substrate for sensing, minimization and bandwidth enhancement[1]. These substrates improve antenna performance. It is high impedance substrate used to integrate low profile antenna. The high impedance of metamaterial is used to prevent unwanted radiation in a low profile antenna and it gives high efficiency[2-6]. Metamaterial substrate is applicable in various applications. Metamaterial behaves as very high dielectric constant substrate to minimize the antenna size[7]. Electromagnetic fields are controlled by metamaterial substrate. Radiated power is enhanced by metamaterial in an antenna.it consists of closed ring resonator and SRR[8]. In the multiband coplanar antenna CPW fed is used and it consist of closed ring resonator and split ring resonator(srr). SRR is common to metamaterials. In various types of metamaterials up to 200 terahertz they produce magnetic response[9]. A single cell SRR at opposite end has a pair of enclosed loops with splits. the loops have a small gap and made up of non-magnetic metal like copper[10]. The loops are gapped and square field pattern obtained is dipolar. Splits in the ring support wavelength than diameter.in closed rings it would not happen[11]. Large capacitance is produced by the small gaps between the rings. This produces low radiative loss[12]. Fig. 1: Split ring resonator (SRR) 281
In this paper multiband compact planar antenna is designed and simulated for2.1/3.5/5ghz. The return loss obtained is more than -10db and the bandwidth is widened from 3.1 to 10.6 GHz[13]. II. PROPOSED ANTENNA DESIGN A multiband compact planar antenna is designed for 2.1/3.5/5GHz and simulated. The proper parameters for the proposed antenna configuration were: r1 = 4.1 mm, r2 = 7.75 mm, t = 0.5 mm, w = 1.6 mm, s = 1 mm, h = 0.5 mm, ωf = 1.5 mm, g = 0.5mm, a = 10.432 mm, b = 8.6 mm, H = 1.6 mm. The CPW feed line proposed in this antenna is indicated in fig 2 and proposed antenna design with ground plane is indicated in fig 3. Fig. 2: Ground plane with feed line Fig. 3: Proposed antenna design with ground plane III. SIMULATED RESULT OF PROPOSED ANTENNA The proposed antenna was designed at (2.1/3.5/5)GHZ and simulated by using ADS software. Following the above design procedure of the proposed antenna a satisfactory result is obtained. Fig. 4: Comparison of simulated and Measured Return loss in db (1 to 6 GHz) 282
Fig. 5: Comparison of simulated and Measured Return loss in db (1 to 11 GHz) The return loss obtained by the proposed antenna is-18db at 2.1 GHz, -22db at 3.5 GHz and -12db at 5GHz is indicated in fig 4. From Fig 4and 5 fabricated antennas shows better result but deviation in frequency of resonance designed. Fig. 6: Proposed fabricated antenna Fig. 7: Current Distribution of Rectangular ground structure antenna As shown in Fig 7: the current is distributed mainly along the edge of the loops and the ground plane, we can obtain a very wide frequency band and improve the impedance matching by adjusting the geometry of the ground plane to decrease the capacitive effect. Therefore semicircular ground and rectangular ground planes are proposed. 283
Fig. 8: VSWR Value Fig. 9: Comparison of proposed antenna with reference antenna in Return loss in db VSWR value in Fig 8 and the return loss curves in Fig. 9 shows that proposed antenna has better response and also the size is reduced where all the other parameters are optimized. A. Radiation Pattern The 2-D radiation patterns shows as in Fig 11, and Fig 12 that the proposed antenna has high directivity, gain and efficiency. Fig. 10: Gain and Directivity of the proposed antenna 284
Fig. 11: 2-D radiation pattern of E-phi Fig. 12: 2-D radiation pattern of E-theta IV. CONCLUSION A new compact and planar multiband antenna with composite micro strip met material resonators has been presented. The antenna is suitable for multi-band mobile devices and offers advantages in small size, planar, inexpensive and ease to manufacture, sample antenna with frequency notched function is proposed for trainband WiMAX wireless communications applications. By using composite closed-ring resonator and SRR to produce three discontinue resonant frequency bands; the antenna is suitable for UMTS, WiMAX and WLAN (2.1/3.5/5GHz) wireless communication. To improve impedance bandwidth and impedance matching, the antenna is fed by 50Ω CPW with tapered impedance transformer line. REFERENCES [1] Y. Li, M. F. Iskander,, Z. Zhang,, and Z.Feng, A New Low Cost Leaky Wave Coplanar Waveguide Continuous Transverse Stub Antenna Array Using Metamaterial-Based Phase Shifters for Beam Steering, IEEE Trans. Antennas Propag., vol. 61, no. 7, pp. 3511 3518,July. 2013. [2] A. Dhouibi, S. N. Burokur and A. Lustrac,, Compact Metamaterial-Based Substrate-Integrated Luneburg Lens Antenna, IEEE Antennas and Wireless Propagation Letters, vol. 11, pp. 1504-1507, 2012. [3] A. B. Ochetan, G. Lojewski, A novel power divider based on the composite right/left handed metamaterial transmission line, for gsm and umts applications, U.P.B. Sci. Bull., Series C, Vol. 73, Iss. 3, pp. 141-150, 2011. 285
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